Add unit tests for various options and validators

[shibayan]

This pull request primarily adds comprehensive unit tests for several core components in the codebase, including options validation, fluent API extensions, registries, paginator logic, and exception handling. Additionally, it includes a minor code style update for collection initialization. These changes aim to improve test coverage, ensure reliability, and modernize code style.

Unit tests for core components:

• Added extensive tests for the options classes (e.g., InputOptions, ConfirmOptions, PasswordOptions, SelectOptions, ListOptions, MultiSelectOptions) to verify correct validation logic and error handling in various scenarios.
• Introduced tests for the paginator, covering navigation (next/previous item and page), filtering, selection, page size changes, and looping behavior.
• Added tests for the Optional<T> struct to verify its value semantics and creation logic.
• Added tests for the fluent API extension methods on options classes, ensuring that chaining and property setting work as intended.
• Introduced tests for registry classes (EnumMetadataRegistry, ModelBinderRegistry) to verify registration and retrieval behavior. [1] [2]
• Added tests for the PromptCanceledException class to ensure constructors and properties behave as expected.

Code style improvements:

• Updated the initialization of the Validators property in PropertyMetadata to use the modern collection initializer syntax ([] instead of new()).

Test refactoring:

• Refactored the MoveToPreviousWord test in TextInputBufferTests to use a helper method for buffer initialization, improving readability and maintainability.

[Copilot]

Pull request overview

Adds a broad set of new unit tests across Sharprompt’s core validation/options and internal utilities, plus a couple of small modernization/style tweaks (collection expressions) and a minor test refactor.

Changes:

• Added new test suites for validators, options validation, fluent extensions, registries, paginator behavior, optional/value helpers, and PromptCanceledException.
• Refactored TextInputBufferTests to reuse a helper for cursor-position setup and added a few additional buffer behavior tests.
• Updated a couple of collection initializations to modern C# collection expression syntax.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
Sharprompt/Internal/OffscreenBuffer.cs	Uses collection expressions for initializing the output buffer.
Sharprompt.SourceGenerator/PromptBindableGenerator.cs	Modernizes Validators list initialization in generator metadata.
Sharprompt.Tests/ValidatorsTests.cs	Adds unit tests for Validators behaviors.
Sharprompt.Tests/ValidatorsExtensionsTests.cs	Adds tests for internal validators list merge helper.
Sharprompt.Tests/TypeHelperTests.cs	Adds tests for nullability detection and invariant conversions.
Sharprompt.Tests/TextInputBufferTests.cs	Refactors buffer setup and adds coverage for Clear, MoveToStart, MoveToEnd.
Sharprompt.Tests/PromptCanceledExceptionTests.cs	Adds constructor/property tests for PromptCanceledException.
Sharprompt.Tests/PaginatorTests.cs	Adds extensive paginator navigation/filtering/page-size tests.
Sharprompt.Tests/OptionsTests.cs	Adds EnsureOptions validation tests for option types.
Sharprompt.Tests/OptionalTests.cs	Adds tests for Optional<T> semantics and factory methods.
Sharprompt.Tests/ModelBinderRegistryTests.cs	Adds tests for registering and retrieving model binders.
Sharprompt.Tests/FluentExtensionsTests.cs	Adds tests for fluent options extension methods/chaining.
Sharprompt.Tests/EnumMetadataRegistryTests.cs	Adds tests for enum metadata registration and retrieval.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.